Automatic mold clamp



July 18, 1950 M. H. KALINA AUTOMATIC MOLD CLAMP 2 Sheets-Sheet l Filed July 9, 1947 July 18, 1950 M. H. KALINA 2,515,654

AUTOMATIC MOLD CLAMP Filed July 9, 1947 2 Sheets-Sheet 2 C' @j w@ @D /1 LHHUL LL Patented July 18, 195() y UNITED STATE AUTOMATIC MOLD CLAMP MartinA H. Kalina, Chicago, Ill.,l assignor, by mesne assignments, to Wetherill `Engineering Company, Philadelphia, ware Pa., a corporation of `Delai Application .Tilly 9, 1947, serial Nol 759,819

VThis invention relates to an automatic mold clamp, and more particularly to a-clamp for use in counter gravity casting for holding mold sections in properly assembled relationship preparatory to and during the casting of metal therein.

In the counter gravity casting of metal as more fully described and lclaimed in my application for patent Serial No. 745,822, iiled May 3, 1947, nowabandoned, gas permeable moldsare positioned within a bell subjected to sub-atmospheric pressure and molten Vmetal is drawn up into said molds under the differential pressure so produced. Since the same bell may be usedfior different sizes and shapes ofY molds, it has heretofore been suggested to provide a Sylphon or bellows controlled diaphragm for clamping the molds, or mold sections, in place within the bell, asfor instance in the Poulter-U. S. Patent No. 2,379,401, issued Junel2`6, 1945. with my present invention, however, I provide an automatic clamping means that is coextensive with the area confined by the bell and adaptable to the clamping of moldsof varying sizes, heights and congurations. The clamp is so constructed that it automatically holds the molds, or mold sections, in assembled relationship when the bell is positioned in place andmaintains said molds, or mold sections, in such relationship duringv the casting operation. My automatic clamping device thus does away with `the necessity of providing individual clamps for the various molds lthat may be assembled within the bell and thereby eliminates considerable labor in the casting operation` V f It is therefore an important object of thisinvention to provide an automatic mold clamp that is self-adjusting to various heights and congurations of molds and that holds the molds, or mold sections in properly assembled relationship within a housing therefor. A

It is a further important object of this invention to provide a mold clamp in connection with counter gravity casting for automatically holding mold sections in assembled relationshipduring the casting operation. n y n Other and further important objects ofthis invention will be apparent from the disclosures in the specincation and the accompanying. drawings.

On the drawings:

In accordance' 7 Claims. (Cl. 22-73) view taken substantially along the line III-III of Figurel.

' Figure 4 is an enlarged bottom plan View of a'main plate used in my mold clamp assembly.

Figure 5 is an enlarged bottom plan viewof one of the side plates used in my mold clamp assemby.

As shown on the drawings:

The reference numeral I0 indicates generally a lbell such as is used in the counter gravity casting apparatus described and claimed in my application Serial No. 742,923, filed April 21, 1947, now abandoned; Said bell I0 comprises a' metal housing, preferably rectangular in shape, and `having an open lower end dened by the bottom edges Ii of the sidewalls I2, Said bell I0 in its operative' lposition is adapted to rest by gravity -upon a platform I3, preferably formed of metal 'and comprising a flat plate of substantially greater dimensions than the area dened by the bell I. Said bell I0 is provided with a sidewall connection afforded by a pipe I4 to a suitable source of vacuum (not shown) for subjecting the interior of the bell to reduced pressure, as is necessary in counter gravity casting. Spring-like guiding fingers I are provided adjacent the lower edge of the bell I0 for properly aligning the bell with respect to the platform I3, `the outer edges I6 oi which are adapted to be engaged by the bowed ends of said ngers as the bell is lowered into place on the platform. Sealing means, indicated generally by the reference numeral Il, are provided for sealing the lower edges II of the bell. Said sealing means Il are more specifically described and claimed in my copending application v for patent Serial No. 742,923, filed April 2l, 1947,

Figure 1 is a vertical sectional View, partly in elevation, illustrating a portionoi counter gravity casting apparatus embodying the principles of my invention. Fligure 2 is a bro-ken, enlarged, fragmentar sectional view of the top vof the bell housing illustrating an automatic mold clamp such as shown in Figure 1. Y y 5 FiguregS is lanfenlarged fragmentary sectional now abandoned.l

The platform I3 is provided with an aperture I8, with which registers a gate assembly I9, including a refractory gate portion 20. Said gate portion 20 has a lower projecting end 2I` that is adapted to be submerged beneath the surface o-f molten metal 22 contained within a Vessel 23. Moldrunner sections 24 and 25.are usually positioned upon the platform I3 for providing communication between the inner gate portion 2U and sectional molds indicated generally by the reference numerals 26 and 21. 'Said mold runners 24 and 25 in their assembled relationship provide an opening 28 registering with the opening formed by the upper end of the gate portion 2U, and runners 29 having vertical openings 39 and 3I for ow communication with the risers 32 of the molds 26 and 21. Said molds 26 and 21 are usually formed in sections,` such as the sections A, B and C.

The mold clamp of my present invention takes the place ofindividual clamping means for holding the mold sections A; B and C in assembled relationship during the casting operation. If

3 clamps were not provided, the pressure of the molten metal that is drawn up into the mold cavity would cause the mold sections to separate. I therefore provide an automatic mold clamp, which is indicated generally by the reference numeral 33, and which is supported from the upper Wall 34 of the bell. Said mold clamp 33 comprises a flexible diaphragm 35, which is preferably formed of two sheets of rubber, or other suitable flexible and distensible material. Said diaphragm 35, comprising the rubber sheets 35 and 31, is supported about its periphery in spaced relationship to the upper wall 34 of the bell by means of corner strips 38, which extend completely around the inside of the bell, and bolts 39 that extend through the upper wall 34 and through the margins of the diaphragm 35. As best shown in Figure 2, thin strips of metal 49 areinserted between the margins of the two rubber sheets 35 and 31 and are perforated to provide for passage of the bolts 39. Thesefmetal strips 46 serve to reenforce the margins of the diaphragm 35 and to prevent the sheets 36 and 31 from being bonded together at their margins under the action of the bolts 39. The lower ends 4of said bolts 39 extend into marginal strip sections 4|`that lie up against the sidewalls l2 of the bell ||l but are not directly secured to said sidewalls. The margins of the diaphragm 35 are thus held securely between said margin strips 4| and the under surface of the corner strips 38 by means of the bolts 39.

In order to prevent the diaphragm 35 from being unduly stretched where it does not exert any clamping action, a plurality of bolts 42 are provided at spaced intervals for extending through enlarged apertures 43 into engagement with said diaphragm 35. As best shown in Figure 2, each of said bolts 42 is provided with a nut 44 on its upper end and carries an apertured Unthreaded disk 45 that is secured to the upper surface of the diaphragm 35 by means of a nut 41. A spacing sleeve 46 surrounds the portion of each bolt 42 below the upper wall 34 of the bell and rests upona nut 41 that bears against a washer 66, resting upon the disk 45. Each spacing sleeve 46 is of such diameter as to pass freely through the corresponding opening 43.when the bolt 42 and nut 41 are raised by turning down a nut 44. The lower end of each bolt 42 extends through the diaphragm 35 and serves to attach to the underside thereof certain protecting members that will noW be described.

The marginal strips 4| extend the full length and width of the bell I9 along the sidewalls I2 thereof and are formed with inwardly projecting tongues 48 (Fig. 2). Marginal plates 49 extend alongside the strips 4| and are provided with grooves 50 for receiving the tongues 48. Said plates 49 thus intert with the strips 4|, but only loosely so as to provide for relative movement therebetween. Similar loose intertting relationship is provided between the plates 43 and other plates 5|, referred to as main plates,

that are positionedinwardly of said plates 49. The marginal plates 49 are secured to the diaphragm 35 by bolts 52. The main plates 5| cover substantially the entire under surface of the diaphragm 35 and are anchored to and supported f kthe under surface of the diaphragm 35 and the f upper surface of the plates. Said asbestos layer 53 may comprise a loose unfelted sheet of variable thickness as indicated in Figure 2. The lower end of each of the bolts 42 is threaded through one of the plates 5| and is provided with a nut 54 on its lower end which serves to lock the bolt and the corresponding plate 5| rigidly together.

Each of the plates 5| is provided on its under surface with a plurality of grooves 55, which may extend substantially the full dimension one way of the plate, except in the middle thereof where a countersunk recess 56 and an opening 51 is provided for the bolt 42 and nut 54. The purpose of the grooves 55 is to permit sub-atmospheric pressure to extend over the upper surfaces of the molds 26 and 21, when such molds are in place and the bell Il] is subjected to sub-atmospheric pressure.

Each of the plates 5| may suitably be formed of aluminum with a tongue 58 extending around two adjacent sides thereof and with a groove 59 extending around the other two adjacent sides. In this way each of the plates 5| interts with an adjacent plate, or a plurality of such adjacent plates. As previously stated, the tongue and groove connection is sufficiently loose to permit relative displacement of one plate 5| with respect to its adjacent plate.

With the mold sections in place, as indicated in Figures 1 and 2, and with sub-atmospheric pressure applied to the interior of the bell |J, the mold clamp 33 automatically adjusts itself to the height and disposition of the molds 26 and 21 due to the atmospheric pressure on the upper side of they mold clamp 33. The enlarged openings 43 provide for communication with the atmosphere of the space, indicated at S, above the diaphragm 35. Consequently, the pressure of the atmosphere is exerted through the diaphragm 35 and those plates 5| that contact the upper surfaces of the molds 26 and 21, such as the plates P (Fig. 1). The other plates 5| not in contact with the molds 26 and 21 may sag slightly, Ias indicated by the plates P (Fig. l).

In order to make the mold clamp 33 adjustable to different heights of molds, the bolts 42 project slightly above the upper wall 34 of the bell so that the nuts 44 at their upper ends are spaced thereabove. At the same time, the diaphragm 35 cannot sag more than the distance represented by the spacing of the nuts 44 from the wall 34, since the nuts 44 are too large to pass through the apertures 43. In order to hold the diaphragm 35 from sagging, some or all of the nuts 44 may be turned down until they engage the upper surfaces of the tops of the sleeves 46. Thus, any particular plate 5| may be drawn up' to a height approximately equivalent to that of strips 4| and be prevented from sagging when the bell IG is subjected to sub-atmospheric pressure.

Since there is some danger of hot metal escapingv from the molds 26 and 21, and since these molds get comparatively hot when filled with molten metal, it is desirable to protect the under surface of the diaphragm 35 by the layer 53 of heat insulating material and also by the metallic plates 49 and 5|. It would be possible, however, to use the diaphragm by itself if the material from which the diaphragm were made were sufficiently heat resistant, without employing the heat insulating layer 53 and the plates 49 and 5|. The plates, however, serve to contact the upper surfaces of the molds 26 and 21 and to transmit thereto the differential between atmospheric pressure in the space S and subatmospheric pressure in the interior of the bell l0. At the same time the grooves 55 permit subatmospheric pressure to be substantially coextensive with the upper surfaces of the molds 26 and 2l that may be in contact with particular plates so that the sub-atmospheric pressure may extend through the gas permeable mold walls.

Although mold sections will be chosen that add up to substantially the same height, it will be appreciated that the total heights of the various molds that may be used in the bell l0 will vary slightly, and it is to accommodate these different heights of molds and different arrangements and spacing of the molds that my automatic mold clamp is provided. As the bell Ill is lowered into place on the platform I3 the mold clamp 33 also comes into contact with the tops of the molds 2B and 21 and adjusts itself to the particular heights and spaced arrangements of said molds. Then, after suction is applied through the connection I4 to the interior of the bell ll), the atmospheric pressure in the space S acts against the upper surface of the diaphragm 35 to exert the differential pressure against the mold sections A, B and C of the molds 26 and 2l to hold said sections tightly clamped together. thus preventing any escape of the molten metal as it enters the cavities of the molds through the mold runners 29 land the risers 3| and 32.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the apy pended claims.

I claim as my invention:

1. In a, bell housing for counter-gravity casting in a mold contained in said housing, a ilexible diaphragm for contacting the side walls of said housing and extending therebetween, rigid articulated members having loosely intertting edges and capable of relative movement carried by the mold side of said diaphragm for contacting said mold, and means for supporting said diaphragm Within said housing.

2. In a bell housing for a sectional mold the improvement of means for automatically clamping and holding said mold sections in assembled relation, said means comprising a flexible diaphragm extending across said housing for ilexing movement toward and away from said mold, a plurality of intertting rigid articulated members capable of movement relative to one another carried by said diaphragm for movement therewith to bear againstthe top of said mold and means limiting the extent of flexing movement of said diaphragm.

3. In a bell housing for subjecting a sectional mold of gas permeable structure to reduced pressure, the improvement of an yautomatic clamping device for urging said mold sections into tightly assembled relationship, said device comprising a iiexible diaphragm in spaced relationship to the top of said housing and subject to atmospheric pressure on its upper side, heat insulating means on the underside of said diaphragm and articulated loosely interfltted plates capable of movement relative to one another carried by said diaphragm and adapted to bear against the top of said mold sections under the differential pressure exerted by the balancing of atmospheric pressure against reduced pressure in said housing.

4. In a bell housing for subjecting a sectional mold of gas permeable structure to reduced pressure, the improvement of an automatic clamping device for urging said mold sections into tightly assembled relationship, said device comprising a exible diaphragm in spaced relation to the top of said housing and subjected to atmospheric pressure on its upper side, bolts extending freely through the top of said housing and anchored at their lower ends to said diaphragm to permit flexing movement of said diaphragm toward and away from the top of said housing, and heat insulating means on the underside of said diaphragm.

5. A mold clamp for maintaining a mold in position within a vacuum bell comprising a plurality of spaced individual suspending members extending through said bell, a diaphragm freely suspended from said members within said bell for flexing movement in a vertical plane, and articulated plates carried by said diaphragm and extending on the mold side thereof, each of said plates having edge portions interfitting with corresponding portions of adjacent plates to accommodate flexing movement of said diaphragm by displacement of each plate relative to the ad-v jacent plates.

6. In a vacuum housing for a mold for countergravity casting of metal, the improvement of a clamp for automatically holding said mold in said housing, said clamp comprising a flexible diaphragm subject to differential pressures urging said diaphragm towards said mold, articulated rigid members secured to the under surface of said diaphragm for contacting said mold, means limiting the extent of movement of said diaphragm, said rigid members having loosely interfitting edge portions for relative movement therebetween, thereby locally rigidifying said diaphragm without interfering with exing movement thereof.

7. In a vacuum housing having side walls and a top wall for enclosing a sectional mold placed therein, the improvement of a clamp for automatically holding said mold in assembled relationship, said clamp comprising a flexible diaphragm extending across said housing in spaced relation from the top thereof to contact the side walls of said housing and subject to differential pressure urging said diaphragm toward said mold, a plurality of loosely intertted plates secured to said diaphragm and movable therewith for contacting said mold, and means extending from said top wall through said diaphragm and secured to said plates for limiting the extent of vertical movement of said diaphragm and said plates within said housing.

MARTIN H. KALINA.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 711,210 Honiss Oct. 14, 1902 1,834,101 LeMay Dec. 1, 1931 2,075,054 Podel Mar. 30, 1937 2,088,123 Toman July 27, 1937 2,379,401 Poulter June 26, 1945 

